*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
/*清楚间距*/

.clearfix:before,
.clearfix:after{
    content: "";
    display: block;
    clear: both;
}
/*清楚浮动*/

li{
    list-style: none;
}
/*去除列表项符号*/

a{
    text-decoration: none;
}
/*去除A标签默认下划线*/


.electric{
    width: 505px;
    margin: auto;
}
.nav li{
    float: left;
    margin: 10px;
    cursor: pointer;
    font-family: David, serif;
}
.nav .active{
    border-bottom: 1px solid orangered;
    font-weight: bold;
}
.main .a1{
    color: orangered;
}
.main a{
    color: #000;
}
.main > div{
    display: none;
}
.main > div.active{
    display: block;
}